Definitely warranted. You see, we don't have quads in the USA (which I'm assuming you're referring to from your "Americans" comment, even though the term encompasses a region of 36 countries to include Costa Rica). We don't have dirt bikes or motorcycles either, so make sure you don't let your guard down if you see one of those approaching. We actually have only recently adapted the ability to operate motorized vehicles with the evolutionary development of opposable thumbs. Please continue to be patient with us as we learn to control these mechanical, wheeled, horse-machines and if luck will have it no pedestrians will be endangered in the process.
We'll return the virtue of patience towards Canadians that are trying to learn to surf ;)
For anyone still trying to get info about quads, try to negotiate the price - some places will do weekly rentals for sub $300.